Tubular heat exchanger



Aug. 27, 1963 A. HUET 3,101,930

I TUBULAR HEAT EXCHANGER Filed Sept. 8, 1959. 2 Sheets-Sheet 1 FIG. 2F\G.3

INVENTOR ANDRE HUET Aug. 27, 1963 A. HUET 3,101,930

TUBULAR HEAT EXCHANGER Filed Sept. 8, 1959 r 2 Sheets-Sheet 2 FIG. 4

FIG. 5

INVENTOR ANDRE HUET BYEM W ATTO 'EY United States Patent Ofiice3,161,930 Patented Aug; 27, 1963 3,101,930 TUBULAR HEAT EXCHANGER AndrHuet, 48 Ave. du Fresident Wilson, Paris, France Filed Sept. 8, 1959,Ser. No, 838,485 Claims priority, application France Sept. 10, 1958 1Claim. (Cl. 165-143) This invention relates to heat exchange apparatusand particularly to improved, distributing header arrangements for abank of tube assemblies each providing an annular passage for one fluidand a central space through which the other fluid flows as well as overthe outer tube surfaces.

The present invention is embodied in a tubular heat exchanger for theexchange of heat between two fluids.

While the heat exchange presents a large exchange surface, the generalarrangement of the tube assemblies and the distributing headers whichfeed the annular passages of said tubes, is such as to occupy a verycompact volume. The connections between the bank of tubes arranged inrows and the headers also permits in the 1ntroduction of cleaningdevices through the ends of the exchanger casing to clean the outersurfaces of the annular tubes as well as the central space through whichthe outer fluid also flows.

Such an exchanger is planned particularly for the exchange of heatbetween two fluids; one of which must be utilized in as small a quantityof volume as possible because of its cost. For instance, this exchangerwill be utilized in a thermal installation associated with employing anexpensive chemical fluid and exchanging its heat with an inexpensivefluid such as ordinary water.

The following description when read in conjunction with the accompanyingdrawings of an illustrative embodiment will afford an understanding ofthe manner in which the invention can be carried out.

FIGURE 1 is a longitudinal section, partially schematic, of a heatexchanger embodying the invention.

FIGURE 2 is a transverse sectional view of the exchanger on the line 2-2of FIGURE 1 showing the tube bundle from the left with the end coverremoved.

FIGURE 3 is a view on a larger scale of a portion of FIGURE 2 and showsthe tube rows, seen from the end in FIGURE 2.

FIGURE 4 shows schematically on a larger scale than in FIGURE 1 thedistribution of fluid to feeding the annular spaces of the exchangertubes from the sub-headers and also shows the annular form adopted forthe tubes.

FIGURE 5 shows the staggered arrangement of tubes a, b, c and d.

As seen in FIGURE 1, the exchanger is contained in a cylindrical casingwith removable end closures 12 and 14. Within this casing is placed anest or bank of tubes placed in staggered fashion in parallel rows asshown in FIGURES 2 and 3. The whole bank arranged in the form of aparallelipiped rectangle is fed, on the one hand, with the heatingfluid, entering via a header 16 and leaving via a header 18, the flowbeing in the direction of the arrows A. The fluid, taking heatcirculates in the direction of the arrows B, from the inlet 20 to theoutlet 22. This second, heated fluid circulates over the tube nest andis confined within a parallelipipedic shell or envelope 24 havingremovable end plates 26, 28 so that the envelope 27 entirely surroundsin fluid tight fashion as seen in FIGURES l and 2, the tube nest and theheaders therefor except for minor parts of the latter.

The tube assemblies 30 are arranged in staggered rows a, b, 0 etc.,according to horizontal planes. In FIGURE 1 the tubes of odd rows areheavily outlined and shaded while tubes of even rows are drawn lightlyor indicated by center lines to facilitate reading the drawing. Thesetube assemblies are preferably constituted by two concentric tubes 32,34 (FIG. 4) and it is in the interval 36 between both concentricenvelopes that the expensive heating fluid circulates. Plain water orother fluid to be heated passes around the outer envelope 32 of tubeassembly I, FIGURE 4, and also within the inner tube 34. Within theinner tube 34 may be placed a deflecting core 38 which has, as we know,the advantage of improving the heat exchanger by producing pulsations inthe circulation. Likewise, deflecting bands of corrugated metal, formingdeflectors or baffles, may be introduced in the spaces between the tubeassemblies 30 to create pulses in the fluid which circulates exteriorly.

The original arrangement of the exchanger resides in the mode of liaisonoi the exchanger tubes with the circuit A.

With the view of disposing the fluid circuit constituted by the tubebundle in the smallest space possible, the exchanger tube assemblies arevery closely spaced as seen in FIGURES 2 and 3. The heating fluidarrives via the header 16' split into two branches 4t}, 42 situated, asseen in FIGURES l and 2, on the vertical and longitudinal symmetry planeof the exchanger. The outlet is through the header 18, itself assemblingtwo branch headers 44, and 46, arranged in the same way on the oppositeend of the exchanger tube bundle. From either side of each inlet header40 and 42 and at the same height level on each header are paralleltransverse sub-headers extend ing laterally to the side boundaries ofthe tube bank. FIGURE 2 may be seen at the inlet header 40 and theparallel transverse sub-headers 50, 52 which are fed by it. The similararrangement of the header '42 and its transverse headers 54, 56 ishidden entirely in FIG. 2 by 40 and 50, 52.

Generally speaking, header 42 feeds by means of the transversesub-headers 54, 56 the odd rows a, c of tubes 30. The header 40 feeds bymeans of the sub-headers 50, 52 the even rows b, d of tubes 30.

Referring to FIGURE 4 it is seen that a tube 30 of the odd row a has itsannular space 36 fed by a duct 60 connected to the sub-header 54 of theheader 42. At the other end of the annular space 36, a pipe 62 joinsthis space to the transverse sub-header 64 leading into the outletheader 44. The tube 30 of the even row b located below the similar tubeof row a is fed by a duct 66, connecting its annular space to thesub-header 50 leading from the inlet header 4i and a duct 68 at theoutlet end joins this tube of the even row b to the transverse subheader70 of the outlet header 46. Thus, as has been said and as seen more indetail in FIGURE 3 which represents the inlet transverse headers 50(which hide the transversal sub-headers 54- of the header 42 situatedimmediately behind); each header 50 feed by means of ducts 66 the tubes30 of the even rows, 12, d which are seen represented by broken lines inFIGURE 3 because they are hidden by the header 50 located next below.The tubes of the rows a and c, are seen in full lines in FIGURE 3, andare fed by the ducts 60 from the sub-headers 54 concealed by thesubheaders Si) in FIGURE 3.

This arrangement of the sub-headers 50, 5'4, and the ducts re, 66 isadopted in order that, when it is desired to proceed with cleaning theexchanger tubes, after having taken off the end closures 1'2 and 14 andthe plates 26, 28 at the end of the parallelipipedic shell 24, throughwhich the heated fluid flows, so as to expose the interiors 34 of thetubes 30* of the odd rows a, 0 shown between the headers 59, as forinstance in FIGURES 2 and 3. Cleaning devices may then be introduced inthese interiors 34. And, likewise, there still remains (FIGURES 2 and 3)between the exterior of the tubes of the odd rows a, c and feed ducts asand 60 a space allowing the introduction of devices to clean the outerparts of tubes in row a.

Internally and externally all the tubes of the odd rows can then becleaned from this side of the exchanger.

From the other end of the exchanger, after taking out the plate 28, thesimilar arrangement of the subheaders 64, 70 and the ducts 62 and 68exposes the interiors and the exteriors of the tubes 30 of the even rowsb, d which can be cleaned.

The ducts 60, 62 and 66, 68 connecting the annular spaces 36 of thetubes to the sub-headers, are, as We can see in FIGURE 4, arched in sucha manner as to permit a certain tolerance due to differences inexpansion. It is to be noted that, for each tube 30, at least one of theconnecting ducts (-62 for the tubes of the odd rows) is longer and morestrongly bent than the other (e.g. 60). It is the inverse, namely, theinlet duct 66 which is more bent for the tubes of the even rows.

The exchanger is shown in horizontal position in the drawings but itcould be more or less inclined to the horizontal by placing it on aproper foundation, for instance, to facilitate the circulation of thefluid within the interiors 34- of the inner tube of each assembly 30.

I claim:

A heat exchanger in which two fluids flow at cross currents andembodying a casing containing a bank of generally horizontal rows ofrectilinear tubular elements with the elements in adjacent rows arrangedin staggered relation, all the tubular elements of said bank being madeup of a pair of concentric tubes joined at their two ends to form anannular space for one fluid, called inner fluid, and a central spacethrough which the other fluid, called outer fluid, flows from theinterior of said casing as well as around the exterior of each tube,inlet and outlet headers for the inner fluid arranged vertically at theopposite ends of the bank of tubes and each being bifurcated to providetwo parallel branches disposed perpendicularly to the axis of the tuberows and situated in the same vertical plane; vertically spaced pairs ofsubheaders fixed perpendicularly on the branches of each bifurcate withthe subheaders of each pair disposed in horizontally spaced relation atthe same height on the one and the other branch, the distance betweenvertically spaced pairs of subheaders being substantially equal todouble 'the distance between two horizontal tube rows to leave clear theends of one tube row out of two and the inlet and outlet headers beingrelatively arranged so as to leave clear the ends of each tube row atopposite ends; bent connections between the subheaders and the tubes ofthe rows they supply, said tube rows being situated below the relatedsubheaders at the inlet end and above the related sub-headers at theopposite end, said connections being shifted in a vertical directionwhen passing from a sub-header mounted on one of the branches of thebifurcate to the similar sub-header mounted on the same level on theother branch of the same bifurcate so as to be clear of the odd numberedrows of tubes at one end of the exchanger and of the even numbered rowsof tubes at the other end of the exchanger.

References Cited in the file of this patent UNITED STATES PATENTS996,130 Pelton Jan. 27, 1911 1,537,271 Strombaclc May 12, 1925 1,674,850Bogardus June 26, 1928 1,884,778 Lucke et al Sept. 25, 1932 2,093,825Bach Sept. 21, 1937 2,640,686 Brown June 2, 1953 2,983,260 I-Iuet May 9,1961 FOREIGN PATENTS 828,108 France Feb. 7, 1938'

